Merge pull request #231 from crawley/filter-fix

Fix for 1 bug and 1 issue in FilterInitMiddleware.  Plus a unit test!
Merge pull request #233 from crawley/filter-command

Added a 'runfilters' django command
Checkpoint of code to handle custom archive organizations
Checkpoint ... organization support mostly working apart from unit tests
Completed the unit test changes, and added some testing for 'tar' format
Added documentation and implemented 'filtering out'.  Also fixed a bug
in the way I was wrapping the mapper functions.